2 files changed, 8 insertions, 0 deletions
diff --git a/lib/core/locks.nim b/lib/core/locks.nim
index 0143957ce..392c8aed4 100644
--- a/lib/core/locks.nim
+++ b/lib/core/locks.nim
@@ -9,6 +9,10 @@
 
 ## This module contains Nim's support for locks and condition vars.
 
+
+when not compileOption("threads") and not defined(nimdoc):
+  {.error: "Locks requires --threads:on option.".}
+
 const insideRLocksModule = false
 include "system/syslocks"
 
diff --git a/lib/core/rlocks.nim b/lib/core/rlocks.nim
index 4710d6cf1..34d7687f9 100644
--- a/lib/core/rlocks.nim
+++ b/lib/core/rlocks.nim
@@ -9,6 +9,10 @@
 
 ## This module contains Nim's support for reentrant locks.
 
+
+when not compileOption("threads") and not defined(nimdoc):
+  {.error: "Rlocks requires --threads:on option.".}
+
 const insideRLocksModule = true
 include "system/syslocks"